BMC/Intel-BMC/linux.git/drivers/pwm/core.c, branch dev-5.2

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 18

2019-05-21T09:28:46+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program see the file copying if not write to the free software foundation 675 mass ave cambridge ma 02139 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 52 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Jilayne Lovejoy Reviewed-by: Steve Winslow Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154042.342335923@linutronix.de Signed-off-by: Greg Kroah-Hartman

pwm: Clear chip_data in pwm_put()

2019-05-09T15:09:54+00:00

After a PWM is disposed by its user the per chip data becomes invalid. Clear the data in common code instead of the device drivers to get consistent behaviour. Before this patch only three of nine drivers cleaned up here. Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: Fix deadlock warning when removing PWM device

2019-03-20T11:21:31+00:00

This patch fixes deadlock warning if removing PWM device when CONFIG_PROVE_LOCKING is enabled. This issue can be reproceduced by the following steps on the R-Car H3 Salvator-X board if the backlight is disabled: # cd /sys/class/pwm/pwmchip0 # echo 0 > export # ls device export npwm power pwm0 subsystem uevent unexport # cd device/driver # ls bind e6e31000.pwm uevent unbind # echo e6e31000.pwm > unbind [ 87.659974] ====================================================== [ 87.666149] WARNING: possible circular locking dependency detected [ 87.672327] 5.0.0 #7 Not tainted [ 87.675549] ------------------------------------------------------ [ 87.681723] bash/2986 is trying to acquire lock: [ 87.686337] 000000005ea0e178 (kn->count#58){++++}, at: kernfs_remove_by_name_ns+0x50/0xa0 [ 87.694528] [ 87.694528] but task is already holding lock: [ 87.700353] 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c [ 87.707405] [ 87.707405] which lock already depends on the new lock. [ 87.707405] [ 87.715574] [ 87.715574] the existing dependency chain (in reverse order) is: [ 87.723048] [ 87.723048] -> #1 (pwm_lock){+.+.}: [ 87.728017] __mutex_lock+0x70/0x7e4 [ 87.732108] mutex_lock_nested+0x1c/0x24 [ 87.736547] pwm_request_from_chip.part.6+0x34/0x74 [ 87.741940] pwm_request_from_chip+0x20/0x40 [ 87.746725] export_store+0x6c/0x1f4 [ 87.750820] dev_attr_store+0x18/0x28 [ 87.754998] sysfs_kf_write+0x54/0x64 [ 87.759175] kernfs_fop_write+0xe4/0x1e8 [ 87.763615] __vfs_write+0x40/0x184 [ 87.767619] vfs_write+0xa8/0x19c [ 87.771448] ksys_write+0x58/0xbc [ 87.775278] __arm64_sys_write+0x18/0x20 [ 87.779721] el0_svc_common+0xd0/0x124 [ 87.783986] el0_svc_compat_handler+0x1c/0x24 [ 87.788858] el0_svc_compat+0x8/0x18 [ 87.792947] [ 87.792947] -> #0 (kn->count#58){++++}: [ 87.798260] lock_acquire+0xc4/0x22c [ 87.802353] __kernfs_remove+0x258/0x2c4 [ 87.806790] kernfs_remove_by_name_ns+0x50/0xa0 [ 87.811836] remove_files.isra.1+0x38/0x78 [ 87.816447] sysfs_remove_group+0x48/0x98 [ 87.820971] sysfs_remove_groups+0x34/0x4c [ 87.825583] device_remove_attrs+0x6c/0x7c [ 87.830197] device_del+0x11c/0x33c [ 87.834201] device_unregister+0x14/0x2c [ 87.838638] pwmchip_sysfs_unexport+0x40/0x4c [ 87.843509] pwmchip_remove+0xf4/0x13c [ 87.847773] rcar_pwm_remove+0x28/0x34 [ 87.852039] platform_drv_remove+0x24/0x64 [ 87.856651] device_release_driver_internal+0x18c/0x21c [ 87.862391] device_release_driver+0x14/0x1c [ 87.867175] unbind_store+0xe0/0x124 [ 87.871265] drv_attr_store+0x20/0x30 [ 87.875442] sysfs_kf_write+0x54/0x64 [ 87.879618] kernfs_fop_write+0xe4/0x1e8 [ 87.884055] __vfs_write+0x40/0x184 [ 87.888057] vfs_write+0xa8/0x19c [ 87.891887] ksys_write+0x58/0xbc [ 87.895716] __arm64_sys_write+0x18/0x20 [ 87.900154] el0_svc_common+0xd0/0x124 [ 87.904417] el0_svc_compat_handler+0x1c/0x24 [ 87.909289] el0_svc_compat+0x8/0x18 [ 87.913378] [ 87.913378] other info that might help us debug this: [ 87.913378] [ 87.921374] Possible unsafe locking scenario: [ 87.921374] [ 87.927286] CPU0 CPU1 [ 87.931808] ---- ---- [ 87.936331] lock(pwm_lock); [ 87.939293] lock(kn->count#58); [ 87.945120] lock(pwm_lock); [ 87.950599] lock(kn->count#58); [ 87.953908] [ 87.953908] *** DEADLOCK *** [ 87.953908] [ 87.959821] 4 locks held by bash/2986: [ 87.963563] #0: 00000000ace7bc30 (sb_writers#6){.+.+}, at: vfs_write+0x188/0x19c [ 87.971044] #1: 00000000287991b2 (&of->mutex){+.+.}, at: kernfs_fop_write+0xb4/0x1e8 [ 87.978872] #2: 00000000f739d016 (&dev->mutex){....}, at: device_release_driver_internal+0x40/0x21c [ 87.988001] #3: 000000006313b17c (pwm_lock){+.+.}, at: pwmchip_remove+0x28/0x13c [ 87.995481] [ 87.995481] stack backtrace: [ 87.999836] CPU: 0 PID: 2986 Comm: bash Not tainted 5.0.0 #7 [ 88.005489] Hardware name: Renesas Salvator-X board based on r8a7795 ES1.x (DT) [ 88.012791] Call trace: [ 88.015235] dump_backtrace+0x0/0x190 [ 88.018891] show_stack+0x14/0x1c [ 88.022204] dump_stack+0xb0/0xec [ 88.025514] print_circular_bug.isra.32+0x1d0/0x2e0 [ 88.030385] __lock_acquire+0x1318/0x1864 [ 88.034388] lock_acquire+0xc4/0x22c [ 88.037958] __kernfs_remove+0x258/0x2c4 [ 88.041874] kernfs_remove_by_name_ns+0x50/0xa0 [ 88.046398] remove_files.isra.1+0x38/0x78 [ 88.050487] sysfs_remove_group+0x48/0x98 [ 88.054490] sysfs_remove_groups+0x34/0x4c [ 88.058580] device_remove_attrs+0x6c/0x7c [ 88.062671] device_del+0x11c/0x33c [ 88.066154] device_unregister+0x14/0x2c [ 88.070070] pwmchip_sysfs_unexport+0x40/0x4c [ 88.074421] pwmchip_remove+0xf4/0x13c [ 88.078163] rcar_pwm_remove+0x28/0x34 [ 88.081906] platform_drv_remove+0x24/0x64 [ 88.085996] device_release_driver_internal+0x18c/0x21c [ 88.091215] device_release_driver+0x14/0x1c [ 88.095478] unbind_store+0xe0/0x124 [ 88.099048] drv_attr_store+0x20/0x30 [ 88.102704] sysfs_kf_write+0x54/0x64 [ 88.106359] kernfs_fop_write+0xe4/0x1e8 [ 88.110275] __vfs_write+0x40/0x184 [ 88.113757] vfs_write+0xa8/0x19c [ 88.117065] ksys_write+0x58/0xbc [ 88.120374] __arm64_sys_write+0x18/0x20 [ 88.124291] el0_svc_common+0xd0/0x124 [ 88.128034] el0_svc_compat_handler+0x1c/0x24 [ 88.132384] el0_svc_compat+0x8/0x18 The sysfs unexport in pwmchip_remove() is completely asymmetric to what we do in pwmchip_add_with_polarity() and commit 0733424c9ba9 ("pwm: Unexport children before chip removal") is a strong indication that this was wrong to begin with. We should just move pwmchip_sysfs_unexport() where it belongs, which is right after pwmchip_sysfs_unexport_children(). In that case, we do not need separate functions anymore either. We also really want to remove sysfs irrespective of whether or not the chip will be removed as a result of pwmchip_remove(). We can only assume that the driver will be gone after that, so we shouldn't leave any dangling sysfs files around. This warning disappears if we move pwmchip_sysfs_unexport() to the top of pwmchip_remove(), pwmchip_sysfs_unexport_children(). That way it is also outside of the pwm_lock section, which indeed doesn't seem to be needed. Moving the pwmchip_sysfs_export() call outside of that section also seems fine and it'd be perfectly symmetric with pwmchip_remove() again. So, this patch fixes them. Signed-off-by: Phong Hoang [shimoda: revise the commit log and code] Fixes: 76abbdde2d95 ("pwm: Add sysfs interface") Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal") Signed-off-by: Yoshihiro Shimoda Tested-by: Hoan Nguyen An Reviewed-by: Geert Uytterhoeven Reviewed-by: Simon Horman Reviewed-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: Drop per-chip dbg_show callback

2019-01-10T08:34:12+00:00

This callback was introduced in commit 62099abf67a2 ("pwm: Add debugfs interface") in 2012 and up to now there is not a single user. So drop this unused code. Signed-off-by: Uwe Kleine-König [thierry.reding@gmail.com: remove kerneldoc for ->dbg_show()] Signed-off-by: Thierry Reding

pwm: Don't use memcmp() to compare state variables

2019-01-10T08:32:23+00:00

Given that struct pwm_state is sparse (at least on some platforms), variables of this type might represent the same state because all fields are pairwise identical but still memcmp() returns a difference because some of the unused bits are different. To prevent surprises compare member by member instead of the whole occupied memory. Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding

pwm: Silently error out on EPROBE_DEFER

2017-07-06T06:29:16+00:00

In of_pwm_get(), if we fail to get the PWM chip due to probe deferal, we shouldn't print an error message. Just be silent in this case. Signed-off-by: Jerome Brunet Reviewed-by: Andreas Färber Signed-off-by: Thierry Reding

pwm: Try to load modules during pwm_get()

2017-01-30T08:36:42+00:00

Add a module name string to the pwm_lookup struct and if specified try to load the module using request_module() if pwmchip_find_by_name() is unable to find the PWM chip. This is a last resort to work around drivers that can't - and can't be made to - deal with deferred probe. Signed-off-by: Hans de Goede [thierry.reding@gmail.com: rename new macro, reword commit message] [thierry.reding@gmail.com: add comment explaining use-case] Signed-off-by: Thierry Reding

pwm: Don't hold pwm_lookup_lock longer than necessary

2017-01-30T08:19:26+00:00

There is no need to hold pwm_lookup_lock after we're done with looping over pwm_lookup_list, so release it earlier. Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding

pwm: Make the PWM_POLARITY flag in DTB optional

2017-01-30T08:13:34+00:00

Change the PWM chip driver registration so that a chip driver that supports polarity inversion can still be used with DTBs that don't provide the polarity flag as part of the specifier. This is done to provide polarity inversion support for the pwm-imx driver without having to modify all existing DTS files. Signed-off-by: Lothar Wassmann Signed-off-by: Bhuvanchandra DV Suggested-by: Sascha Hauer Signed-off-by: Lukasz Majewski Reviewed-by: Boris Brezillon Signed-off-by: Thierry Reding

pwm: Print error messages with pr_err() instead of pr_debug()

2017-01-30T08:13:30+00:00

Make the messages that are printed in case of fatal errors actually visible to the user without having to recompile the driver with debugging enabled. Signed-off-by: Lothar Waßmann Signed-off-by: Bhuvanchandra DV Reviewed-by: Boris Brezillon Signed-off-by: Thierry Reding